Do you have TrackIr installed?
To use Flyinside XP the option to use TrackIR must be disabled in your equipment settings.
Otherwise I saw the cockpit shaking and the roll axis of my viewpoint was shifting by itself when I looked at the rendering options screen.
Till this gets done automatically Flyinside could you put this info in a sticky?
If you don't know how to disable TrackIr look at the second post in this thread.
viewtopic.php?f=17&t=3641